Sample preparation is an essential stage in many analytical processes. Preparation procedures may involve, for example, removal of undesired components present in the sample, exchanging one solvent in which an analyte is dissolved for another solvent or concentrate an analyte among other things. Solid Phase Extraction (“SPE”) is one such sample preparation procedure that may be used for sample extraction, concentration and cleanup. Typical SPE devices utilize packed beds of sorbent contained between porous filter discs within a SPE tube.
When nonaqueous liquids are used in SPE processes, it is generally desirable that the tubes be constructed of a material that will not dissolve or leach contaminants into the nonaqueous liquid. Ultra-clean polypropylene has been traditionally used, however, the inventors show herein that when using a nonaqueous liquids, contaminants are dissolved or leached from polypropylene SPE tubes and from high density polyethylene SPE tubes as well. Thus, there is a need for SPE tubes that are substantially inert and do not dissolve or leach contaminants into nonaqueous liquids.